The present invention relates generally to media and apparatus used to carry electrical and optical signals. More particularly, the present invention relates to media, such as cabling, and apparatus, such as connectors, cable assemblies, circuit boards, and systems used for transporting electrical and optical signals from one location to another.
High-speed microprocessor systems give rise to the need for high-speed signal interfaces. While microprocessor clock operational speeds now routinely exceed 1 GHz, off-board input/output interfaces typically run at speeds of less than 100 MHz. This limitation exists, in part, due to crosstalk which appears between adjacent electrical channels. While electrical conductors can be spaced apart to reduce the problem somewhat, the loss of circuit board surface area and connection density may not be tolerable in a particular design. Over distance, signal amplitude loss and noise also become a problem.
Optical media may carry signals having modulation frequencies in excess of several GHz without appreciable loss of signal strength or an increase in noise over distance. However, a purely optical interface is often not required for routine interface operations.
Thus, there is a need in the art to provide a flexible signaling medium, including connectors and connector assemblies, which offer both electrical and optical signal connection capability. Such a medium should accommodate low and high bandwidth signals, permitting the designer to trade bandwidth for cost. The medium should also operate to minimize electromagnetic interference between signals.